DType

DType is the factory object for creating data type descriptors.

Overview

import { DType } from "molniya";

// Non-nullable types
DType.int32
DType.float64
DType.string

// Nullable types
DType.nullable.int32
DType.nullable.string

Non-Nullable Types

Property	Storage	JavaScript Type
DType.int8	1 byte	number
DType.int16	2 bytes	number
DType.int32	4 bytes	number
DType.int64	8 bytes	bigint
DType.uint8	1 byte	number
DType.uint16	2 bytes	number
DType.uint32	4 bytes	number
DType.uint64	8 bytes	bigint
DType.float32	4 bytes	number
DType.float64	8 bytes	number
DType.boolean	1 byte	boolean
DType.string	4 bytes*	string
DType.date	4 bytes	Date
DType.timestamp	8 bytes	bigint

* String columns store a 4-byte dictionary index.

Nullable Types

Access nullable variants through DType.nullable:

DType.nullable.int32
DType.nullable.float64
DType.nullable.string
DType.nullable.boolean
// ... etc for all types

Nullable types allow null values in the column and use an additional null bitmap.

Usage in Schemas

import { DType } from "molniya";

const schema = {
  // Required fields
  id: DType.int32,
  name: DType.string,
  price: DType.float64,
  
  // Optional fields (can be null)
  description: DType.nullable.string,
  discount: DType.nullable.float64
};

Type Interface

interface DType<K extends DTypeKind = DTypeKind> {
  readonly kind: K;
  readonly nullable: boolean;
}

Helper Functions

isNumericDType()

Check if a type is numeric (supports arithmetic).

import { isNumericDType, DType } from "molniya";

isNumericDType(DType.int32)    // true
isNumericDType(DType.float64)  // true
isNumericDType(DType.string)   // false

isIntegerDType()

Check if a type is an integer (not floating point).

import { isIntegerDType, DType } from "molniya";

isIntegerDType(DType.int32)    // true
isIntegerDType(DType.float64)  // false
isIntegerDType(DType.string)   // false

isBigIntDType()

Check if a type uses BigInt representation.

import { isBigIntDType, DType } from "molniya";

isBigIntDType(DType.int64)      // true
isBigIntDType(DType.uint64)     // true
isBigIntDType(DType.timestamp)  // true
isBigIntDType(DType.int32)      // false

getDTypeSize()

Get the byte size of a type.

import { getDTypeSize, DType } from "molniya";

getDTypeSize(DType.int32)    // 4
getDTypeSize(DType.float64)  // 8
getDTypeSize(DType.string)   // 4 (dictionary index)

toNullable()

Convert any type to its nullable variant.

import { toNullable, DType } from "molniya";

const nullableInt = toNullable(DType.int32);
// Equivalent to DType.nullable.int32

Type Mapping

The DTypeToTS type maps DType kinds to TypeScript types:

import type { DTypeToTS, DTypeKind } from "molniya";

type Int32Type = DTypeToTS<DTypeKind.Int32>  // number
type Int64Type = DTypeToTS<DTypeKind.Int64>  // bigint
type StringType = DTypeToTS<DTypeKind.String> // string

See Also

• DTypeKind - Type identifiers enum
• Data Types Guide - When to use each type